The present invention relates generally to agricultural equipment, and more particularly to a simple and effective method and apparatus capable of simultaneously transplanting a plurality of seedlings from a centralized location to a plurality of spaced apart rows.
The transplanting of seedlings is virtually as old as farming. Initially transplanting was accomplished manually, with the farm worker digging a hole in the ground and then placing the seedling in the hole. However, efforts have been made to mechanize this agricultural activity, early activities being illustrated in U.S. Pat. No. 85,195 issued Dec. 22, 1868 and U.S. Pat. No. 120,801 issued Nov. 7, 1871. In U.S. Pat. No. 85,195 the seedlings to be planted are placed on a belt of a horse drawn transplanter, the transplanter including means to open and close a furrow in the ground. The seedlings to be transplanted are picked up roots first from the endless belt by a setting wheel, and are then set in the furrow in a vertical position with their roots down. U.S. Pat. No. 120,801 shows that the seedlings to be transplanted may pass by gravity through a pipe or tube.
While early transplanters were drawn by draft animals, transplanting equipment today is either self-propelled, or, more commonly, drawn by tractors. U.S. Pat. No. 3,446,164 to Huang et al issued May 27, 1969 discloses an automatic two row transplanter. This device as illustrated discloses a tractor drawn carrier, although it is disclosed that it may be self-propelled. The Huang et al transplanter includes, in addition to furrow openers and press wheels for each row, two pairs of drop tubes, there being one pair of drop tubes for each row. A vacuum source is connected to each drop tube so that a vacuum may be applied thereto. The seedlings to be transplanted are carried in grid trays which rest upon a grid bearing plate of the transplanter. The grid bearing plate is provided with apertures, there being one pair of apertures for each pair of drop tubes. During operation, only one grid tray is associated with each pair of apertures. Thus, there is one tray for each row. A first indexing mechanism is provided to control longitudinal movement of the grid bearing plate and a second indexing mechanism is provided to control transverse movement of the grid trays so that in turn each seedling in each tray will move over the apertures and be drawn into the drop tubes by the applied vacuum and then pass therethrough. The drop tubes are provided with one way valves below the vacuum source. The potted seedlings pass through the one way valves, which valves prevent reverse air flow to the vacuum source. Once the seedlings have passed the one way valves in the drop tubes, inertia and gravity will cause them to continue their movement towards and into open furrows. Once the grid trays on the transplanter are empty, the transplanting cycle has been completed, and the transplanter must be stopped and the grid trays reloaded. After this is accomplished the transplanting operation can commence for another cycle. Other related Huang patents are U.S. Pat. No. 3,712,252, U.S. Pat. No. 4,186,671, and U.S. Pat. No. 5,254,140.
Huang also discloses that it is desirable to transplant plants having air-pruned root systems. Many papers have been written about air-pruning one of which is xe2x80x9cIncrease Crop Production and Automation Using Properly Designed Air-pruning Trays/Containersxe2x80x9d (Agricultural Mechanization in Asia, Africa and Latin America, Vol. 29, No. 2, pp. 42-50 (1998). Related patents and published applications which disclose apparatus for planting air-pruned plants are U.S. Pat. No. 5,179,800, U.S. Pat. No. 5,254,140, CN 1,078,847, U.S. Pat. No. 5,431,116, AU 662,964, and U.S. Pat. No. 5,573,558. The apparatus disclosed in these various patents all use essentially the same concepts discloses in U.S. Pat. No. 3,446,164, and have the same basic disadvantages of U.S. Pat. No. 3,446,164. Thus, the seedlings which are to be discharged are not positively handled once they pass the source of vacuum within the discharge tube.
This requires that the number of components and moving parts for feeding the plants to be multiplied by the number of rows, thus resulting in high initial cost and operating maintenance costs. To perform the indexing of the tray and plant extraction, most of the previous systems utilized sensors, servos and computers. In the environment planters operate in, electronic sophistication quickly becomes an on-going maintenance problems. Because of this sophistication, highly trained and expensive labor is needed to keep the planters running. In addition, the prior apparatus requires that the planting unit be stopped once the grid trays on the transplanter are empty. Physical size of the indexers and planter components limit the adaptability of the planter to be set up for differing regional needs. Furthermore, physical limitations, as to how fast the system can run without component damage and transplant damage, has many times reduced the potential labor savings and economic benefit of an automatic planter.
Other patents which are conceptually similar to U.S. Pat. No. 3,446,164 are U.S. Pat. Nos. 4,770,111, 5,209,170, 5,241,917, and 5,445,089. Another transplanter is shown in U.S. Pat. No. 4,941,416. However, none of these patents overcome the disadvantages of U.S. Pat. No. 3,446,164 set forth above.
It is an object of the present invention to provide a transplanter employing a novel method and apparatus of transplanting which overcomes many of the disadvantages of the prior art.
More particularly, it is an object of the present invention to provide a transplanter which is capable of transplanting seedings to a plurality of transversely spaced apart rows from a single centralized source of seedlings.
It is a further object of the present invention to provide a transplanter in which seedlings are transported from a common source initially under negative air pressure to an intermediate ejector chamber, and then under positive air pressure to the ground to insure positive handling of the seedlings.
Another object of the present invention is to provide a pneumatic plant transfer system and seedling tray support design which can be readily modified, so that seedlings to be transplanted can be planted in a selected number of rows at the same time, such as two rows, three rows as illustrated in the accompanying figures, or more rows even up to 10 or more.
It is yet another object of the present invention to provide a transplanting apparatus which is of relative low cost and of high durability.
In summary, the present invention utilizes a single centralized feeder which will feed anywhere from 2 to 10 or more rows of seedlings at one time. The centralized feeder concept allows a machine to operate with low velocity movement and still plant large numbers of seedlings per hour (i.e. 10,400 per 2 row unit and 54,000 per 10 row unit). The present invention utilizes open bottom plant trays provided with air pruned type seedlings. These plant trays are designed so that the seedlings can be extracted from the bottom of the trays, seedlings for all rows being extracted from a single tray, or during a transition from one leading tray to another following tray, from two adjacent trays. The tray s are supported on a support which is in turn carried by a carrier which is adapted to be propelled in a forward direction across the ground which is to receive the seedlings. The carrier in the illustrated embodiment is a tractor drawn tool bar. The carrier also carries a plurality of transversely spaced apart soil openers for creating seedling receiving openings in the ground. Means are provided for transporting the seedlings from the centralized feeder to the opened ground, the transport means including an impulse-type extraction system and a pneumatic seedling transfer system. This new system is simple in concept and has only two moving parts per row. The real merit of the concept is its ability to extract seedlings from a centralized feeder and transfer the seedlings to individual row units through conduit tubes, one per row. To minimize sophistication, the xe2x80x9cXxe2x80x9d and xe2x80x9cYxe2x80x9d movements of the indexer utilize a simple mechanical cam, ratchet, and eccentric design. Low velocity movement of the mechanical components result in a system with much more durability and longevity. This concept makes the transplanter system extremely adaptable to almost any configuration, for example 2-10 or more rows, bare ground fields, mulch covered beds, and even to other manufacturer""s planters. The transplanter is equipped with a full tray magazine and an empty tray magazine to either side of a longitudinally movable cross table. In order avoid the necessity of stopping, and to insure that all seedlings in a tray are utilized, before one full tray has been completely emptied, a full tray is transferred from the full tray magazine to the indexer behind the tray being emptied so that it can be fed with the almost emptied leading tray, and when the leading tray has completed its movement across the cross table, the emptied leading tray is transferred to the empty tray magazine. This avoids the necessity of stopping the unit when one or two trays have been emptied.